Brake accelerator



Mar. 20, 1923..

BRAKE ACCELERATOR Filed July 21, 192-0 1,449,002 W. HILDEBRAND PatentedMar. 21), 1923.

STATES PATENT oFrieE.

WILHELLM HILDEBRAND, F BERLIN, GERMANY, ASSIGNOR TO KNORR-BREMSEAKTIIENGESELLSGHAFT, OE LICHTENBERG, BERLIN, GERMANY.

BRAKE ACCELERATOR.

Application filed July 21, 1920.

' at None Bahnhofstrasse 917, Lichtenherg,

Berlin, 0. 112, Germany, have invented certain new and usefulImproven'ients in Brake Accelerators (for which I have received patentsas follows: Germany, 1 0. 301,944, May 4, 1917'; Austria, No. 78,468,June 18, 1917; Hungary, No. 74,148, June 18, 1917; Sweden, No. 44,819,June 28, 1917; Switzerland, No. 77.47G June 20, 1917; Italy, No.251/1615, (lot. 15. 1917; Finland, No. 7,807, June 21, 1919), 01? whichthe following is a specificat-ion.

This invention relates to brake accelerators for trains in which theemptying of the transfer chamber can only take place by the employmentof a valve controlled by the pressure in the brake cylinder when thebrake is entirely or almost entirely taken 01?. There this valve isinterposed in the con nection between the train pipe and the transferchamber, this may under certain circumstances have the disadvantage thatthe valve is closed too rapidly and the connection interrupted beforethe equalization is perfect.

According to the present invention the valve is placed on the reliefpipe of the chamber, so that the connection between the train pipe andthe chamber not interrupted, and consequently a perfect equalizm ti onbetween the train pipe and the chamber is rendered possible, but theemptying of the chamber can only take place when the brake though theinlet of the transfer chamber is solely controlled by the triple valve.

In the drawing is shown a diagrammatic view of the subject matter of theinvention. Figures 1 and 1 show the brake in the brake off position.

Serial No. 398,040.

Figures 2 and 2" the brake in the brake on position.

The compressed air admitted to the continuous brake pipe L passestherefrom through the branch pipe Z into the chamber- I of the triplevalve S, pushing the piston a with the slide valve 6 into the "righthand extreme position, and then passes on through the groove madein theusual way into the chamber II and the auxiliary air reservoir Hconnected thereto. With the triple valve S is connected the brakecylinder B through the pipe 0 and also through the pipes g and g;between the latter pipes the minimum pressure valve is interposed, andthe pipe 0 in the position shown in Figure 1 communicates through arecess in the slide valve 17) with the pipe which leads to the open air.The chamber I is also connected by a second recess in the slide valvewith the pipe f and consequently with the pipe 9, which communicatesthrough the minimum pressure valve and pipe 9 with 0 and thereforelikewise with the outer air. The valve 0 of the minimum pressure valveM, which controls the communication between the pipes g and is open inthis position, namely when the brake is in the brake otl position, asthe chamber III below the differential piston (Z (Z which controls thevalve 0 communicates with the open air through the branch pipe it andthe pipe 0 which serves to take the brake oil. In this position of thetriple valve the branch pipe Z is closed by the slide valve. Theopenings of the dilierent ports in the face of the valve, and also theposition of the slide valve relatively to them, can be seen in plan inFigure 1 If new for the purpose of applying the brake, ainbe allowed toescape from the pipe L the piston a and the slide valve 6 of the triplevalve will move into the position shown in Figures 2 and 2. hand thiscauses the branch pipe Z leading from the train pipe to be connectedthrough a recess in the slide valve with the transfer chamber K so thatthe pressure in both chambers is equalized. At the same time the pipe 7leading to the outer air is closed and the mouth of the pipe 9 leading.to the brake cylinder exposed, so that the compressed air can passthroufi the now open mlnlmum pressure valve into the brake cylinder B.When a slight previously On the one s determined initial pressure isattained in the latter, the pressure exerted on the larger face of thedifferential piston preponderates in the chamber III and closes thevalve 0. The further increase of pressure in the brake cylinder B takesplace in the Well known way through special recesses and passages in theslide valve and special connections which are not shown. If nowcompressed air be admitted into the train pipe L for the purpose ofpartially taking the brake oil, the piston a together with the slidevalve F) moves back into its right hand position, in which the chamber Kis connected by the pipe 6, the recess in the slide valve and the pipe fwith the pipe 9. Now as the valve 0 is still closed by the pressurewhich exists in the brake cylinder and acts upwardly on the differentialpiston (Z (Z the pressure in the chamber K is maintained, and it canonly escape when the pressure in the brake cylinder has become so lowthat the pressure in the chamber K on the cross sectional area of thesmall valve overcomes the pressure in the brake cylinder on the largeface of the diflerential piston d d At this instant the brake ispractically entirely taken off. The

compressed air in the chamber K then escapes along with the compressedair in the cylinder B through the pipe 0, the recess in the slide valveand the pipe 7 into the open air. If however the brake is not completelyreleased, but the braking effect is weakened by temporary inception vofthe release position of the triple valve, although the slide Z) placesthe chamber K in connection with the pipe g], the valve 0 still preventsemptying of the chamber K because the pressure in the brake cylinder isonly reduced to such an extent that the combined pressure from thetransfer chamber K and auxiliary reservoir ll act ing on the valve 0 areinsufficient to overcome the pressure from the brake cylinder acting onthe piston (Z What I claim and desire to secure by Letters Patent of theUnited States is 1. In a bralreaccelerator, a transfer chamber receivingair from the train pipe when an application of the brakes is initiated,a valve controlled by the pressure in the train aaaooa pipe andcontrolling the connection of the said pipe with the said chamber, arelief pipe for the transfer chamber, and a valve controlling saidrelief pipe.

2. In brake accelerator for triple valves provided with a minimumpressure valve, a transfer chamber receiving air from the train pipewhen an application of the brakes is initiated, a valve controlled bythe pressure in the train pipe and controlling the connection of thesaid pipe with the said chamber, a relief pipe for the transfer chamber,said relief pipe being also controlled by the last named valve andconnected to the port which leads from the auxiliary air reservoir tothe minimum pressure valve when the triple valve is in the brake onposition, the minimum pressure valve conjointljv controlling the outletof the transfer chamher.

3. In brake accelerating apparatus for trains of vehicles, a train pipe,a transfer chamber having a relief pipe, air connections between thesaid'train pipe and the said chamber, a brake cylinder and a valvecontrolled by air pressure in the said cylinder and in turn controllingthe said relief pipe.

4:. In brake accelerating apparatus for trains of vehicles, a trainpipe, a transfer chamber having a relief pipe, air connectionsbetweenvthe said train pipe and the said chamber,a brake cylinder, avalve controlled by air pressure in the said cylinder and in turncontrolling the said relief pipe, an auxiliary air reservoir and airconnections between the said reservoir and the said valve.

In brake accelerating apparatus for trains of vehicles, a train pipe, atransfer chamber, an auxiliary air reservoir, a brake cylinder, a triplechambered valve, air con nections between the said cylinder and the twoouter chambers of the said triple chainbered valve, an air chamberhaving pipes connecting it with all the foregoing parts and with theatmosphere, and a reciprocating recessed slide valve in the said airchamber controlling the openings of all the said connecting pipes, forthe purposes specified.

WILHELM HILDEBRAND.

